1. Field of the Invention
The present invention relates to a method of inspecting and evaluating the degree of failure in a structural material, e.g., metal due to fatigue by a nondestructive inspection technique.
2. Description of the Prior Art
A variety of nondestructive inspection methods have heretofore been utilized for the purpose of evaluating the soundness of materials to be inspected, e.g., various materials and structures with respect to their structural construction, quality, strength as well as their shape, etc., by utilizing the detected results of their physical properties without destroying the materials or structures being inspected. The principal nondestructive inspection methods heretofore used for material inspection purposes may for example by classified as follows.